Television channel change picture-in-picture circuit and method

ABSTRACT

We describe and claim television channel change picture-in-picture circuit and method. The circuit includes means for displaying a first channel on a primary portion of a screen, means for changing from the first channel to a second channel, and means for displaying the second channel on a secondary portion of the screen responsive to the means for changing from the first to the second channel while continuing to display the first channel on the primary portion of the screen.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.11/190,216, filed on Jul. 26, 2005, titled TELEVISION CHANNEL CHANGEPICTURE-IN-PICTURE CIRCUIT AND METHOD, which is incorporated herein byreference in its entirety.

FIELD

This application relates to television systems and, more particularly,to a television channel change picture-in-picture circuit and method.

BACKGROUND

A typical television (TV) has a plurality of buttons to actuateassociated features. One such feature is channel changing actuated bypressing a channel up or a channel down button on, e.g., a TV's remotecontrol or front panel. The user presses the channel up or down buttononce for each channel up or down, respectively, he desires to view.Every time the user presses the channel up or down buttons, the channeldisplayed on the TV prior to the press is replaced with the currentlyselected channel. That is, the TV displays the currently selectedchannel with each channel up or down button press, no longer displayingpreviously selected channels.

FIGS. 1A-D are illustrations of a TV 160's display as the user changesselected channels. FIG. 1A is a display of the user's current channel 2selection. After the user presses the channel up button once, the panel160 replaces channel 2 with a display of channel 6 (FIG. 1B). After theuser presses the channel up button again, the panel 160 replaces channel6 with a display of channel 8 (FIG. 1C). After the user presses thechannel up button yet again, the panel 160 replaces channel 8 with adisplay of channel 10 (FIG. 1D). And so on. After each channel change,the TV replaces display of the previous channel with a display of thecurrent channel.

During channel surfing, the user scans a series of television channelsto find something eye catching or to avoid commercials. It is desirableto channel surf without replacing the television's display of thecurrently selected channel at every channel change button press.

Accordingly, a need remains for a TV channel change picture-in-picturecircuit and method.

BRIEF DRAWINGS DESCRIPTION

We describe embodiments referencing the following drawings.

FIGS. 1A-D are illustrations of a TV 160's display as the user changeschannels.

FIG. 2 is a block diagram of an embodiment of a television system 100.

FIG. 3 is a block diagram of an embodiment of the controller 150 shownin FIG. 2.

FIGS. 4A-E are illustrations of a TV 160's display as the user changeschannels using an embodiment of a TV channel change picture-in-picturecircuit and method.

FIG. 5 is a flowchart of an embodiment of a channel changepicture-in-picture method.

DETAILED DESCRIPTION

FIG. 2 is a block diagram of an embodiment of a television system 100.Referring to FIG. 2, the system 100 includes a receiver 120 forreceiving an analog image data signal 110, e.g., RGB or YP_(B)P_(R)signal, from a source 102. The source 102 may be a personal computer107, a digital video disk player 105, set top box (STB) 103, or anyother device capable of generating the analog image data signal 110. Thereceiver 120 may be an analog-to-digital converter (ADC) or any otherdevice capable of generating video signals 109 and/or 111 from theanalog image data 110. The receiver 120 converts the analog image datasignal 110 into the digital video signals 109 and/or 111 and provides itto a controller 150. A person of reasonable skill in the art knows wellthe design and operation of the source 102 and the receiver 120.

Likewise, a video receiver or decoder 122 decodes an analog video signal112 from a video source 104. The video source 104 may be a videocamcorder, tape player, digital video disk (DVD) player, or any otherdevice capable of generating the analog video signal 112. The videosource 104 may read (or play) external media 101. In an embodiment, aDVD player 104 plays the DVD 101. In another embodiment, a VHS tapeplayer 104 plays a VHS tape 101. The decoder 122 converts the analogvideo signal 112 into the video signals 109 and/or 111 and provides itto the display controller 150. The decoder is any device capable ofgenerating the video signals 109 and/or 111 in, e.g., Y/C or CVBSformat, from the analog video signal 112. A person of reasonable skillin the art knows well the design and operation of the video source 104and the video decoder 122.

A modem or network interface card (NIC) 124 receives data 114 from aglobal computer network 106 such as the Internet®. The data 114 may bein any format capable of transmission over the network 106. In anembodiment, the data 114 is packetized digital data. But the data 114may also be in an analog form. Likewise, the modem 124 may be a digitalor analog modem or any device capable of receiving and/or decoding data114 from a network 106. The modem 124 provides video signals 109 and/or111 to the display controller 150. A person of reasonable skill in theart knows well the design and operation of the network 106 and themodem/NIC 124.

A Digital Visual Interface (DVI) or high definition multimedia interface(HDMI) receiver 126 receives digital signals 116 from a digital source108. In an embodiment, the source 108 provides digital RGB signals 116to the receiver 126. The receiver 126 provides video signals 109 and/or111 to the display controller 150. A person of reasonable skill in theart knows well the design and operation of the source 108 and thereceiver 126.

A tuner 128 receives a wireless signal 118 transmitted by the antenna119. The antenna 119 is any device capable of wirelessly transmitting orbroadcasting the signal 118 to the tuner 128. In an embodiment, theantenna 119 transmits a television signal 118 to the television tuner128. The tuner 128 may be any device capable of receiving a signal 118transmitted wirelessly by any other device, e.g., the antenna 119, andof generating the video signals 109 and 111 from the wireless signal118. The tuner 128 provides the video signals 109 and 111 to thecontroller 150. A person of reasonable skill in the art knows well thedesign and operation of the antenna 119 and the tuner 128.

The controller 150 may generate image data 132 and/or control signals133 (collectively data signals 132) by manipulating the video signals109 and 111 or any other signal it receives at its input. The displaycontroller 150 provides the image data 132 to a panel 160 in any of avariety of manners. In an embodiment, the panel 160 is a televisioneither analog (e.g., Cathode Ray Tube (CRT)), digital (e.g., HighDefinition Television (HDTV)), or otherwise. The panel 160 may bedigital with a fixed pixel structure, e.g., active and passive LCDdisplays, plasma displays (PDP), field emissive displays (FED),electro-luminescent (EL) displays, micro-mirror technology displays, lowtemperature polysilicon (LTPS) displays, and the like. The panel 160 maybe other than a digital display, e.g., an analog display such as a CRTas used in monitors, projectors, personal digital assistants, and otherlike applications. For simplicity, we refer to panel 160 as television160 in the following description.

In an embodiment, the controller 150 may scale the video signals 109and/or 111 for display using a variety of techniques including pixelreplication, spatial and temporal interpolation, digital signalfiltering and processing, and the like. In another embodiment, thecontroller 150 may additionally change the resolution of the digitalvideo signal 109, changing the frame rate and/or pixel rate encoded inthe video signals 109 and/or 111. We will not discuss scaling,resolution, frame and/or pixel rate conversion, and/or colormanipulation in any further detail. A person of reasonable skill in theart should recognize that the controller 150 may manipulate the signals109 and/or 111 and provide the image data 132 to the television 160 suchthat it is capable of properly displaying a high quality imageregardless of display or panel type.

Read-only (ROM) and random access (RAM) memories 140 and 142,respectively, are coupled to the display system controller 150 and storebitmaps, FIR filter coefficients, and the like. A person of reasonableskill in the art should recognize that the ROM and RAM memories 140 and142, respectively, may be of any type or size depending on theapplication, cost, and other system constraints. A person of reasonableskill in the art should recognize that the ROM and RAM memories 140 and142, respectively, are optional in the system 100 and may be external orinternal to the controller 150. RAM memory 142 may be a flash typememory device. Clock 144 controls timing associated with variousoperations of the controller 150.

The video signals 109 and/or 111 may be in a variety of formats,including composite or component video. Composite video describes asignal in which luminance, chrominance, and synchronization informationare multiplexed in the frequency, time, and amplitude domain for singlewire transmission. Component video, on the other hand, describes asystem in which a color picture is represented by a number of videosignals, each of which carries a component of the total videoinformation. In a component video device, the component video signalsmay be processed separately and, ideally, encoding into a compositevideo signal occurs only once, prior to transmission. The video signals109 and/or 111 may be a stream of digital numbers describing acontinuous analog video waveform in either composite or component form.FIG. 2 describes a variety of devices (and manners) in which the videosignals 109 and/or 111 may be generated from an analog video signal orother sources. A person of reasonable skill in the art should recognizeother devices for generating the video signals 109 and/or come withinthe scope of the application.

In FIG. 2, the controller 150 is shown as receiving the video signals109 or 111, or both. Alternatively, the controller 150 may receive ananalog signal, e.g., analog image data signal 110 from the video 103,DVD 105, and/or computer 107. In the later case, the controller 150 mayinclude means for receiving and converting the analog signal into adigital signal, e.g., ADC receiver 120 or video decoder 122.

FIG. 3 is a block diagram of an embodiment of the controller 150 shownin FIG. 2. The following description is associated with one embodimentof implementing PIP on a television system 100. But embodimentsdescribed below are capable of implementation in other PIP systems andmethods. All PIP systems and methods known to a person of skill in theart come within the scope of the recited claims.

Referring to FIGS. 2 and 3, the controller 150 may capture signals 109and 111 alternately or concurrently from at least two ports 302 and 304.We show only two ports 302 and 304 for simplicity but a person ofreasonable skill in the art should understand that any number and typeof ports come within the scope of the claims. In an embodiment, theports 302 and 304 receive broadcast video signals for display on thetelevision 160.

The controller 150 may capture signal 109 into a corresponding inputbuffer 306 from the port 302 while it captures signal 111 into acorresponding input buffer 308 from the port 304. In an embodiment, theinput buffers 306 and 308 accumulate data pixels from signals 109 and111, respectively, until the processor 312 indicates to a memoryinterface 311 that it can store them to a frame memory 310. The memoryinterface 311 may control the input buffers 306 and 308 and/or the framememory 310 responsive to the processor 312.

The memory interface 311 may include a plurality of registers 313. Theplurality of registers 113, in turn, may include a picture-in-picture(PIP) enable register (PIPEN) that is automatically set by the processor312 or manually set by a user or manufacturer. When the PIPEN registeris set, the controller 150 may concurrently capture data from the ports302 and 304. The controller 150 may place data from one port, e.g., port302, into a PIP window 320 while placing data from another port, e.g.,port 304, in the active area 318 of the television 160.

A PIP source register (PIPSRC) may indicate which port can write to thePIP window 320. For example, if the PIPSRC is set to 1, the port 302writes to the PIP window 320. And, for another example, if the PIPSRC isset to 0, the port 304 writes to the PIP window 320. Doing so defineswhat is displayed on an active area 318 and on a PIP window 320 of thetelevision 160.

The PIP window 320 may be described and/or located by a plurality ofdescription registers, including top line register (PIPT), horizontalline register (PIPH), the left edge register (PIPL), and width register(PIPW). The PIPT register may indicate the location of the top linewhile the PIPH register indicates the number of horizontal lines in thePIP window 320. The PIPL and PIPW registers may define the left edge andwidth (e.g., in memory words), respectively, of the PIP window 320.

With the PIPSRC set to 1, the port 302 may capture data for the activearea 318 that correspond to the dimensions in memory 311. But the memoryinterface 311 may discard data it captures from the port 302 havingwrite addresses that correspond to the PIP window 320. The port 304, onthe other hand, captures data into the memory 310 having addresses thatcorrespond to the PIP window 320. Although the port 304's origin can betranslated relative to the port 302's origin, the port 304 uses the sameframe memory (and dimensions) as the port 302 in PIP mode. Putdifferently, the memory interface 311 discards data it captures from theport 304 having write addresses outside the PIP window 320. Note the PIPwindow 320 need not match the active area 318 of the port 304's image.

During data capture, the ports 302 and 304 may write data to the memory310 under the control of the memory interface 311 asynchronous to anyclocks, e.g., graphics, video, or memory clocks.

The scalar 316 receives image data that includes the PIP window 320image data pre-inserted through a plurality of first-in first-out (FIFO)line buffers. The scalar 316 scales the image data as a whole, includingthe active area 318 and PIP window 320 image data. The scalar 316 may beframe-locked to either the ports 302 and 304 (or neither), but may useseparate control signaling from that used by the ports 302 and 304. Aperson of reasonable skill knows well the design and operation of thescalar 316. We will not discuss it in any further detail here.

FIGS. 4A-E are illustrations of a TV 160's display as the user changeschannels using an embodiment of a channel change PIP circuit and method.FIGS. 4A-E show the available broadcast signals as those correspondingto channels 2, 6, 8, and 10. FIGS. 4A-E show a channel change sequencethat substantially corresponds with the sequence shown in FIGS. 1A-D,except that FIGS. 4A-E show how the inventive channel change system andmethod described here improves the channel changing experience for theuser.

FIG. 5 is a flowchart of an embodiment of a channel change method 500.

Referring to FIGS. 4A-E and 5, the user may manually activate channelchange PIP mode at block 502 by, e.g., configuring the television 160'son screen display (OSD) capabilities using the remote control 162.Alternatively, the processor 312 may automatically activate channelchange PIP mode by, e.g., setting one of the plurality of registers 313in the controller 150.

The channel change mode allows the controller 150 to operate thetelevision 160 as follows. FIG. 4A is a display of the user's currentchannel 2 selection in the active area 318 of the television 160 (block504).

With the channel change mode activated, the controller 150 determines ifthe user presses a channel change button 164 on the remote control 162(block 506). If the user presses a channel change button, the controller150 causes the television 160 to continue to to display channel 2 in theactive area 318 (block 508) and channel 6 in the PIP window 320 at block510 (FIG. 4B). After the user presses the channel change button 164again (block 506), the controller 150 causes the television 160 todisplay channel 2 in the active area 318 as before (block 508). But thecontroller 150 causes the television 160 to replace channel 6 with adisplay of channel 8 in the PIP window 320 at block 510 (FIG. 4C). Afterthe user presses the channel change button 164 once again (block 506),the controller 150 causes the television 160 to display channel 2 in theactive area 318 (block 508). And the controller 150 causes thetelevision 160 to replace a display of channel 8 with a display ofchannel 10 in the PIP window 320 at block 510 (FIG. 4D).

The user may cancel the channel change mode and/or the PIP mode, usingthe remote control 162 and/or the television 160's OSD. If the usercancels the channel change mode and/or the PIP mode at block 12, thecontroller 150 removes the display of the PIP window 320 on thetelevision 160 at block 514 continuing to display the currently selectedchannel in the active area 318.

If the user selects to view a channel currently being previewed in thePIP window 320 e.g., channel 10, at any time by pressing a correspondingselect button on the remote control 162 (block 516), the controller 150replaces a display of channel 2 with a display of channel 10 in theactive area 318 at block 518 and removes the preview display of thechanged channel in the PIP window 320 at block 520 (FIG. 4E).Alternatively, if the user does not change channels within apredetermined time, e.g., 1 minute or less, the controller 150 mayremove the display of the PIP window 320 on the television 160 and/orreplace the display of the current channel in the active area 318 with adisplay the channel currently previewed in the PIP window 320.

We have illustrated and described the principles of a television channelchange picture-in-picture circuit and method by way of illustrative andnot restrictive examples. Those of skill in the art will recognizecertain modifications, permutations, additions, and sub-combinations tothe exemplary embodiments we describe above. We intend that thefollowing claims and those claims we introduce later be interpreted toinclude all such modifications, permutations, additions,sub-combinations as are within the spirit and scope.

1. A television system, comprising: a receiver for receiving an analogimage data signal from a source and converting the analog image datasignal into first and second digital video signals corresponding tofirst and second channels, respectively; a controller for manipulatingthe first and second digital video signals, the controller comprising:first and second ports for receiving, respectively, the first and seconddigital video signals from the receiver; a frame memory for storing datapixels from the first and second digital video signals; and a memoryinterface for controlling the frame memory, the memory interfacecomprising a picture-in-picture (PIP) source register (PIPSRC), a PIPenable register (PIPEN), a top line register (PIPT), a horizontal lineregister (PIPH), a left edge register (PIPL), and a width register(PIPW); and a panel for receiving the data pixels from the controller,wherein the panel comprises: a primary screen to display data pixelsfrom the first video signal; and a secondary screen within the primaryscreen to display data pixels from the second video signal, wherein thePIPT indicates a location of a top line of the secondary screen, thePIPH indicates a number of horizontal lines within the secondary screen,the PIPL defines a left edge of the secondary screen, and the PIPWdefines a width of the secondary screen.
 2. The television system ofclaim 1, wherein the panel comprises a digital display having a fixedpixel structure.
 3. The television system of claim 1, wherein the panelcomprises an analog display.
 4. The television system of claim 1,wherein the controller further comprises first and second input buffersfor accumulating the data pixels from the first and second digital videosignals, respectively, received by the first and second ports,respectively.
 5. The television system of claim 1, wherein at least oneof the first and second digital video signals is of a composite videoformat.
 6. The television system of claim 1, wherein at least one of thefirst and second digital video signals is of a component video format.7. The television system of claim 1, wherein the controller furthercomprises a scalar for scaling at least some of the data pixels prior tothe controller sending the data pixels to the panel.
 8. The televisionsystem of claim 1, wherein the controller further comprises a processorfor setting the PIPEN.
 9. A method, comprising: displaying a first videobroadcast channel on a primary portion of a screen; responsive to a userpressing a channel change button, changing from the first videobroadcast channel to a second video broadcast channel; and responsive tothe changing and to receiving an indication from a picture-in-picture(PIP) source register (PIPSRC), defining a secondary portion of thescreen based on a top line register (PIPT), a horizontal line register(PIPH), a left edge register (PIPL), and a width register (PIPW),displaying the second video broadcast channel on the secondary portionof the screen while continuing to display the first video broadcastchannel on the primary portion of the screen, wherein the secondaryportion of the screen is smaller than the primary portion of the screen,and wherein displaying the second video broadcast channel on thesecondary portion of the screen is also responsive to receiving anindication from a PIP enable register (PIPEN).
 10. The method of claim9, further comprising setting the PIPEN.
 11. The method of claim 9,further comprising scaling image data corresponding to at least one ofthe first and second video broadcast channels.
 12. The method of claim9, further comprising changing a resolution of image data correspondingto at least one of the first and second video broadcast channels. 13.The method of claim 9, further comprising receiving the first videobroadcast channel through a first port in a controller.
 14. The methodof claim 13, further comprising receiving the second video broadcastchannel through a second port in the controller.
 15. The method of claim9, further comprising: responsive to the user pressing a select button,replacing the first video broadcast channel with the second videobroadcast channel on the primary portion of the screen; and removing thesecondary portion of the screen.
 16. The method of claim 9, furthercomprising removing the secondary portion of the screen after apredetermined amount of time.
 17. The method of claim 16, furthercomprising replacing the first video broadcast channel with the secondvideo broadcast channel on the primary portion of the screen prior toremoving the secondary portion of the screen.
 18. The method of claim16, wherein the predetermined amount of time is one minute.